Examples of measurement apparatuses for measuring a distance to an object to be measured include an apparatus for measurement using measurement light. For example, Patent Literature 1 discloses an absolute distance meter including a light source for outputting a radiation beam (measurement light), a target including an external retroreflector for reflecting the measurement light, a light receiving unit integrally fixed with the light source and receiving the light reflected from the target, and a signal processing unit for analyzing the light received by the light receiving unit to calculate a distance to the target. While the target is in contact with the object to be measured, the absolute distance meter irradiates the target with the measurement light from the light source, receives the light reflected from the target by the light receiving unit, analyzes the received light, and calculates the distance to the target, and thereby can measure the distance to the object to be measured with which the target is in contact.
Patent Literature 2 discloses, as a jig for holding a spherical reflector (target) used for measurement of a bending angle of a rod-shaped workpiece (pipe) such as a cylindrical body or a columnar body, a jig including a pair of semi-circular jig component bodies formed with an outward groove for slidably holding the spherical reflector, and combined with each other to be fitted and mounted on an outer periphery of the pipe. In Patent Literature 2, the target is moved along the jig to facilitate measurement of the bending angle of the rod-shaped workpiece, and further to enable recording of the bending angle of the rod-shaped workpiece for each portion to be measured.